Shape classification method based on the topological perceptual organization theory
Abstract
A shape classification method based on the topological perceptual organization (TPO) theory, comprising steps of: extracting boundary points of shapes (S1); constructing topological space and computing the representation of extracted boundary points (S2); extracting global features of shapes from the representation of boundary points in topological space (S3); extracting local features of shapes from the representation of boundary points in Euclidean space (S4); combining global features and local features through adjusting the weight of local features according to the performance of global features (S5); classifying shapes using the combination of global features and local features (S6). The invention is applicable for intelligent video surveillance, e.g., objects classification and scene understanding. The invention can also be used for the automatic driving system wherein robust recognition of traffic signs plays an important role in enhancing the intelligence of the system.
Claims
exact text as granted — not AI-modifiedThe invention claimed is:
1. A shape classification method implemented by a computing device, comprising the steps of:
S1: extracting boundary points of shapes;
S2: constructing a topological space and computing a representation of the boundary points;
S3: extracting global features of the shapes from the representation of the boundary points in the topological space;
S4: extracting local features of the shapes from the representation of the boundary points in a Euclidean space;
S5: combining the global features and the local features through adjusting weight values of the local features according to performance of the global features;
S6: classifying the shapes using a combination of the global features and the local features.
2. The method of claim 1 , wherein the topological space is defined as:
d*=G ( d ′)
where G is a geodesic distance operator for calculating a geodesic distance and d′ is defined as:
d
′
(
i
,
j
)
=
{
d
(
i
,
j
)
,
if
d
(
i
,
j
)
<
ξ
∞
,
otherwise
where ξ is a largest ignorable distance in visual psuchology and d(i,j) denotes a Euclidean distance between i and j which are two boundary points of a shape.
3. The method of claim 1 , wherein the global features are extracted as:
h
(
k
)
=
∑
i
=
1
n
∑
j
=
i
+
1
n
θ
(
i
,
j
)
,
if
L
(
k
)
≤
θ
(
i
,
j
)
<
U
(
k
)
θ
(
i
,
j
)
=
d
*
(
i
,
j
)
d
(
i
,
j
)
where n is a number of boundary points of a shape, L(k) and U(k) are the lower bound and upper bound of a k th bin of a histogram.
4. The method of claim 1 , wherein the local features of a shape are extracted using a scale-invariant feature transform (SIFT) algorithm.
5. The method of claim 1 , wherein the step S5 comprises:
computing a matching score of global features; and
using a reciprocal of the matching score of the global features as the weight value of the local features.
6. The method of claim 5 , wherein a final matching score between two shapes is defined as:
dis final =dis global +α×dis local
where dis global is a global histogram distance between two shapes which indicates the degree of global matching, dis local is a local histogram distance between two shapes which indicates a degree of local matching and α is the weight value of the local features and is proportional to dis global .
7. The method of claim 1 , wherein the step S6 comprises:
assembling the shapes from a same category; and
separating the shapes from different categories.Cited by (0)
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